United Nations Secretary-General Antonio Guterres has called for an immediate implementation of a Security Council resolution for a 30-day ceasefire in Syria, Al Jazeera reported.

Speaking at the UN Human Rights Council in Geneva, Switzerland, on Monday, Guterres described the situation in Eastern Ghouta as “hell on earth”, as Syrian government forces continue an aerial bombardment campaign in the rebel-held enclave.

“Eastern Ghouta cannot wait, it is high time to stop this hell on earth,” Guterres told the council during the opening of its annual session.

“I remind all parties of their absolute obligation and international humanitarian and human rights law to protect civilians and civilian infrastructure at all times,” he said.

“Similarly, efforts to combat “terrorism” do not supersede these obligations,” he added.

The remarks come as doctors in the enclave accuse the government of launching a chlorine gas attack in the town of Al-Shifaniyah in Eastern Ghouta.

Syria’s Civil Defense, also known as the White Helmets, said on Sunday that at least one child died as a result of suffocation.

According to the Syrian opposition’s health officials, victims were showing symptoms “consistent with exposure to toxic chlorine gas”.

On Sunday, President Bashar al-Assad’s forces launched a ground offensive against opposition groups from multiple fronts, in an attempt to penetrate into the besieged enclave, which has been under rebel control since 2013.

Al Jazeera’s Zeina Khodr, reporting from Beirut in neighbouring Lebanon, said the government has not been able to take “any inch of territory in Ghouta” since the ground offensive began.